IDIOMS

deadbeat dad

(chiefly US and Canada, idiomatic, derogatory) A man, especially one who is divorced or estranged from his partner, who fails to provide monetary child support when he is legally required to do so.

Example: 1995, David Van Biema, "Dunning Deadbeats," Time, 3 Apr.,
  If the '90s offer one villain by consensus, it is the deadbeat dad, that selfish fugitive condemned by liberals and conservatives alike for his irresponsible behavior and generous contributions to the cycle of welfare dependency.